BACILLUS-THURINGIENSIS SPP KURSTAKI AS AN EFFECTIVE CONTROL AGENT OF LEPIDOPTERAN PESTS IN TOMATO FIELDS IN ISRAEL

Chrysodeixes (Plusia) chalcites Esper, which is a major pest of tomato in Israel, was controlled in a series of field applications (5,000 g of 8,000 IU/mg, in 150-200 liter/ha) with strains of Bacillus thuringiensis ssp. kurstaki. All instars were susceptible to B. thuringiensis. Thus, timing of application was not crucial for effective larval control of C. chalcites. Heliothis armigera Hubner usually accompanied the major pest at low to medium population densities (2-4 larvae per meter row). In 38 of 40 commercial fields (2-35 ha each), applications of B. thuringiensis suppressed pest populations to levels below the economic threshold and were comparable with effective chemical pesticides. In tomato fields adjacent to potato fields, extensive damage is caused by the potato tuberworm, Phthorimaea operculella (Zeller). Three consecutive applications of B. thuringiensis at a high volume (500 liter/ha) were required to control this species.